Color Blindness Simulator

Our simulator uses the Brettel et al. algorithm, published in 1997 and widely recognized as one of the most accurate methods for simulating color vision deficiencies. It mathematically transforms the RGB color space to match the reduced color gamut perceived by different types of color blindness, validated against clinical data.

Deuteranopia (Green-blindness) and Protanopia (Red-blindness) are the most common, collectively called Red-Green color blindness. They affect about 8% of men and 0.5% of women globally. Prioritizing these two covers the vast majority of color-blind cases. Tritanopia (Blue-Yellow blindness) is much rarer (<0.01%).

For people with Protanopia or Deuteranopia, the cones in their eyes responsible for detecting red or green light are missing or malfunctioning. This causes the brain to confuse these colors, often perceiving them both as shades of yellow or muddy brown. This is why 'Red' error messages and 'Green' success messages can be indistinguishable without icons.

Yes! Once you upload an image and select a simulation mode, click the Download button to save the processed image as a PNG. This is useful for including in accessibility reports, design documentation, or presenting to stakeholders.

This tool visualizes how designs are perceived, which helps identify potential issues. For strict compliance verification, you should also use our Contrast Checker to ensure text meets the WCAG AA/AAA contrast ratios (4.5:1 for normal text, 3:1 for large text).

Absolutely. All image processing happens 100% locally in your browser using JavaScript and HTML5 Canvas. Your images are never uploaded to any server. You can even disconnect from the internet after loading the page and the tool will still work.

Achromatopsia is complete color blindness, where the person sees the world only in shades of gray. It's extremely rare (1 in 30,000 people) and often accompanied by light sensitivity and reduced visual acuity. We include it for completeness in accessibility testing.

Anomalous Trichromacy refers to people who have all three cone types but one is shifted, causing weakened color perception rather than complete blindness. Examples include Protanomaly and Deuteranomaly (weak red/green vision). Our simulator focuses on the more severe Dichromacy types for clearer results.

Color blindness affects approximately 300 million people worldwide—about 8% of men and 0.5% of women. It's an X-linked genetic condition, which is why men (with one X chromosome) are affected much more frequently than women (who have two).

Currently, there is no cure for color blindness. Some special glasses (like EnChroma) can enhance color perception for certain types, but they don't provide 'normal' vision. This makes accessible design even more important—you can't fix the user, so you must adapt the design.

Avoid relying on these pairs to convey different meanings: Red/Green (most common issue), Green/Brown, Blue/Purple, and Pink/Gray. Instead, use patterns, icons, labels, or varying brightness in addition to color.

Key strategies include: 1) Never use color alone to convey information. 2) Add icons, patterns, or text labels alongside colors. 3) Ensure sufficient contrast (use our Contrast Checker). 4) Test your designs with this simulator before launch. 5) Use distinct hues with different brightness levels.